While researching my new clip art sets, DIY Wildlife Feeders Clip Art and DIY Wildlife Houses, I consulted a few books and websites. Here are a some that I would recommend to help you with your own similar projects. (Note that the books are Amazon affiliate links.)
Wildlife Gardening A DK book by Martyn Cox from 2009; hardcover 80 pp SLJ (School Library Journal) grades 3-6. This book has a lot of projects reasonably within reach of kids, though most with adult help. All the projects seem to have real, practical use in the garden or for STEM explorations. Because it is British, you will want to swap out plants native to your area for their native recommendations.
Kids’ Easy to Create Wildlife Habitats by Emily Stetson, illustrations by J. Susan Cole Stone from 2004; paperback 128 pp SLJ grades 2-5. Filled with information about backyard wildlife and habitats, including modern problems they face, this book also offers many useful, practical projects for making wildlife-friendly spaces.
The Wildlife-Friendly Vegetable Gardener by Tammi Hartung, illustrations by Holly Ward Bimbo from 2013; paperback 144 pp. A book aimed at adults and filled with charming illustrations on every page. Offers ways to encourage wildlife in a peaceful coexistence with your garden. Includes ideas for feeders and shelters.
The website daviddomoney.com offers a free, downloadable PDF guide to making an insect hotel that appeals to a variety of bugs, plus projects to make shelters for solitary bees, lacewings, or ladybugs.
The greatstems.com blog has a nice collection of wildlife projects for kids, including feeders and shelters.
There is good information on bumblebees and their nesting habitats at bumblebeeconservation.org.
My Pinterest board Kid’s Gardening has many other links to related projects.